The present invention relates to a thermal head which is used in printers, facsimiles, and other image-forming apparatuses, and which produces heat in response to an image-forming signal.
Thermal heads of this type generally comprise a plurality of heat-generating resistors, as heating elements, mounted on a glazed ceramic substrate. The heat-generating resistors are connected to a circuit board by means of wires, as electrical conductors. The circuit board causes a current flow through the resistors to generate heat in accordance with image information to be recorded. As a result, the information is recorded on a sheet. In doing this, for example, thermosensitive paper may be used for the sheet, or ink from an ink ribbon may be transferred to the sheet by fusion.
Meanwhile, a ceramic plate with a polished level surface is used for the substrate of the thermal head for the heating elements. In this case, the heating elements must be arranged on one and the same level surface, which is polished with considerably high accuracy.
Thus, according to the prior art thermal heads described above, high-accuracy polishing work for the ceramic substrate requires much labor, resulting in higher cost.
In use, moreover, an ink-ribbon film or other medium is interposed between the thermal head and recording paper. This usually requires some space around the head. It is therefore difficult to provide small-sized printers. Thus, there is an increasing demand for thermal heads which permit reduction in size of printers.